Impeller assembly



Oct. 13, 1964 M. J. WACLAWEK IMPELLER ASSEMBLY 2 Sheets-Sheet 1 FiledAug. 21, 1961 Irv/6712 27:

Oct. 13, 1964 Filed Aug. 21, 1961 M. J. WACLAWEK 3,152,447

IMPELLER ASSEMBLY 2 Sheets-Sheet 2 United States Patent 3,152,447IMPELLER ASSEMBLY Miczyslaw J. Waclawek, Olympia Fields, 111., assignorto Borg-Warner Corporation, Chicago, Ill., a corporation of IllinoisFiled Aug. 21, 1961, Ser. No. 132,781 1 Claim. (Cl. 60-54) Thisinvention relates to hydrodynamic couplings and more particularly to avaned impeller assembly forming part of the hydrodynamic coupling.

Heretofore, difliculty has been experienced in retaining vanes or bladesin operative position in high torque impeller assemblies.conventionally, the vanes or blades have been formed at their outeredges with tabs which are received in registering slots at the impellershell. The inner edges of the vanes or blades have been formed with tabsfor reception in registering openings in a shroud ring and bent over tograsp the ring. By this arrangement, the shroud ring was retained in anoperative position and the vanes or blades were evenly spaced each fromthe other. No positive means other than the vanes or blades themselveshave been used to assure retention of the shroud ring in a positiveposition with respect to the shell.

Other methods of fastening the vanes to the shells have includedclenching preformed teeth on the vanes into the relatively soft surfaceof the shell, or Welding portions of the vanes to the adjacent shroudring or shell. Each of these methods presented severe difliculties whenapplied to high torque impeller assemblies. For example, the welding ofthe vanes to the housing provides too rigid a connection therebetweenwithout permitting a certain amount of flexure to the shell and shroudring to accommodate the high fluid pressures therein.

A primary object of this invention is to provide a hydrodynamic couplinghaving positive means for retaining an impeller, shroud ring and theseveral impeller blades or vanes in proper position and lateralalignment.

A further object of this invention is to provide a vaned element for ahydrodynamic coupling such as a torque converter or the like, inaccordance with the preceding object, wherein the positive securingmeans may be employed without requiring changes in tooling in themanufacture thereof and wherein the efliciency of the fluid movementwithin the vaned element is substantially unaffected.

Another object of this invention is to provide a vaned element for ahydrodynamic coupling device wherein a plurality of circumferentiallyspaced socket portions are provided on one of spaced shell membersthereof and cap screws are adapted to engage the other of said shellmembers while being threadably received in a socket portion. Aparticular feature of this object is the ability of the cap screws andcooperating socket to cause the shell members to apply compressivestresses to the edges of said vanes whereby the conventionalinterengaging tabs and slots of the parts may be maintained in theirusual engaging condition in spite of high operating pressures.

Still another object of this invention is to provide a vaned element ofa hydrodynamic coupling device in which independent positive securingmeans isemployed to maintain said vanes in proper lateral alignmentunder all operating conditions, and which is particularly adapted forease of assembly during manufacture and is adapted to be both economicaland reduce repair costs.

The invention consists of novel construction, arrangements and devicesto be hereinafter described in claims for carrying out the above statedobjects, and such other objects as will appear in the followingdescription of certain typical embodiments of the invention illustratedin the accompanying drawings, wherein:

FIG. 1 is a central sectional and elevational view of a drive mechanismincluding a torque converter and embodying the principles of thisinvention;

FIG. 2 is a fragmentary side view of the construction of FIG. 1 and istaken substantially along line 22 as shown in FIG. 1;

FIG. 3 is an enlarged fragmentary view of the impeller takensubstantially along line 33 of FIG. 1;

FIG. 4 is a fragmentary view taken substantially along line 1-4 of FIG.3;

FIG. 5 is a view similar to that of FIG. 3 and illustrating a modifiedform of the present invention;

FIG. 6 is still another view similar to that of view 3 and illustratinganother modified form of the present invention.

Referring to the drawings and more particularly to FIG. 1, the inventionis illustrated as embodied in a drive mechanism rotatable about an axisAA and operable to transmit drive between an engine crank shaft (no-tshown) and a transmission input shaft 10. The drive mechanism comprisesa torque converter generally indicated at 11 and operably connectedbetween the engine crank shaft and the transmission input shaft 10. Thetorque converter generally has a housing 12 consisting of front and rearsections 13 and 14, each having peripheral flanges 13a and 14arespectively adapted to be secured together so that the sections maydefine a fluid chamber 15 within which is operatively contained fluiddriving and reaction elements of the torque converter.

The front section 13 more particularly comprises a substantiallydished-out member or stamping of sheet metal, such as steel, having amajor radially extending portion 17 which is semi-toroidally shaped; theradially inner extent of the major portion 17 has an annular flat hubportion 13 provided with a central opening 18a therein. A bearing member19 is fastened to the marginal portion of the hub about the centralopening 13a and is in general alignment with the opening; the fasteningmay be accomplished by suitable industrial adhesives such as acontinuous line of welding, as at 19a. The outer extent of the majorportion has the radially extending integral flange 13a containing aplurality of circumferentially spaced openings 21.

The rear section 14 of the torque converter housing more particularlycomprises a cast member of aluminum or the like, and has a major portion22 forming the outer shell of an impeller for the torque converter; theportion is substantially semi-toroidal in shape having an annular flange23 at its radially inner extent and adapted to be fastened to a radiallyextending flange 24 at one end of a sleeve shaft 25 by a plurality offasteners 26. The radial outer extent of portion 22 comprises an axiallyextending cylindrical portion 27 carrying flange 14a at its terminal endand the flange 14a has a plurality of circumferentially spaced openings27 provided therein, in alignment with the openings of flange 13a.Suitable bolts 28 are adapted to be received in said openings forsecuring said flanges together.

More particularly, the driving and reaction elements contained withinthe housing of the torque converter comprise a turbine'3tl, a stator 31and vanes 32 cooperating with the portion on outer shell 22 toconstitute an impeller 33. The turbine 30 is drivingly connected to theinput shaft It) for the transmission. A one way clutch device 34 isdisposed between an intermediate shaft 35 and the stator 31; the one wayclutch may be of any suitable construction and in the illustratedembodiment comprises an inner cylindrical race 36, an outer cylindricalrace 37 and a plurality of tiltable sprags 38 between the races.

The hydraulic torque converter functions to multiply the torque betweenthe crank shaft and the transmission input shaft 10, all of theconverter elements having blades provided with shapes such that they arecapable of providing a toroidal circulation of fluid, whereby the vanesof the impeller 33 impart energy to a body of fluid Within the converterand the turbine 38 receives the energy of the fluid, the stator 31having vanes 39 cooperating with vanes 32 and 40 of the impeller andturbine respectively and having a reaction force impressed thereon bythe fluid, the vanes of the converter elements being etfective, when thestator is held from rotation by the one way clutch 34 to serve as areaction element, to change the direction of flow of the fluid so thatthe converter multiplies torque.

Turning now more particularly to the construction of the impeller, thesubstantially semi-toroidal portion 22 forming the outer shell of theimpeller has a plurality of recesses or receptacles 45 provided in theinner surface thereof, arranged generally in rings (FIG. 2) each ringhaving said recesses circumferentially spaced apart. Spaced from theinner surface of the semi-toroidal shell member is a shroud or core ring46 forming an inner shell member for the impeller and is substantiallysemi-toroidal in shape. The core ring has a plurality of slots 47provided therein and arranged in rings, each ring having the slotscircumferentially spaced. Disposed between the shroud and impeller outershell is the plurality of relatively thin vanes 32 having opposite edges48 and 49 engaged by the outer shell and shroud ring respectively. Saidedges are arcuately shaped so as to mate with the interior surfaces ofthe shroud ring and outer shell and have provided thereon at such edgesor marginal portions a plurality of tabs or projections 51, certainprojections of which are adapted to be received in the recesses of theimpeller outer shell and others of which are adapted to be received bythe slots of the shroud ring.

It is quite important to maintain a predetermined spacing between theouter shell of the impeller and that of the shroud ring during alloperational conditions of the converter. Heretofore, the positioning ofthe vanes has always been assured during such conditions by theinterlocking eifect of the projections received within the outer shellrecesses and accompanied by the effect of the tabs extending through theshroud ring slots and tab ends clinched against the side thereof. Suchfastening means were suflicient to prevent unwanted lateral movement ofthe vanes since the experienced pressure forces caused no substantialdeviation in spacing of the shroud ring from the outer shell of theimpeller during operation.

In response to the desire for higher stall K factors in the design oftorque converters of today, severe high pressure conditions are nowencountered by the vaned elements such as the impeller. Particularlywhere the impeller shell is constructed of sheet metal, such highpressures during operation have a tendency to flex and flatten out theimpeller outer shell as well as the shroud ring during operation. Suchdistortion of the impeller walls may cause the tabs or projections onthe outer arcuate edges of the vanes to withdraw from the recesseswithin the impeller outer shell or slots in the shroud ring and therebypermit the vanes to become dislocated, resulting in severe damage to theimpeller. Under conventional constructions, failures due to dislocationof the vanes have been encountered at 200 ft.-lbs. of torque. Suchlimitation is not adequate to meet the requirements of moderndaydesigns.

To obviate the above problems and yet to retain the condition of arelatively flexible impeller construction, the present inventioncontemplates provision of an independent fastening means which isadapted to cause the shroud ring and impeller outer shell to apply acompressive stress to the outer edges of the vane whereby theinterengagement of the tabs and recesses or slots is assured regardlessof internal fluid forces.

As shown in FIG. 3, the outer shell of the impeller is provided withthree circumferentially arranged socket portions 60 adapted to extendaxially thereof. Each of the socket portions 60 contains a threaded bore60a which faces toward the shroud ring (the preferred embodiment is hereshown to comprise three equi-distantly arranged socket portions but itis contemplated that two or more may be utilized). The socket portionsare located substantially near the intermediate portion of thesemitoroidal curvature of the impeller outer shell.

A plurality of cap screws 62 are adapted to be inserted through openings63 provided in the shroud ring and aligned with the socket bores 60a;each of the cap screws have one end which is adapted to be threadablyreceived by the threaded bores 60a of the socket portions and have anopposite end carrying a head 62a which is adapted to engage one side ofa retainer plate 64 which is substantially flat in shape and has atleast opposite ends 65 and 66 thereof engaging the inner contours of theshroud ring. The retainer plate 64 may be constructed of heavy dutysheet metal and as shown in FIG. 4, has cut out portions 64a adapted sothat it will not interfere or engage the fastening tabs of the vanes.

Since the cap screws will be subject to vibrational forces tending toloosen them, means must be provided to secure them Within their socketsand prevent their unscrewing during operation. A preferred construction,pursuant to this end, is illustrated in FIG. 3 wherein a lock washer 67is sandwiched between the retainer plate 64 and the cap screw head 62ato prevent turning of the cap screw and is used in conjunction with ascrew-thread bonding applied to the threaded end of the cap screw, suchas Loctite.

An alternative embodiment of the independent interengaging means betweenthe shroud ring and impeller outer shell may comprise that shown in FIG.5 in which the cap screw is inserted in the socket portions similar tothat of the preferred embodiment but in place of the retainer plate andthe lock washer is provided a localized application of welding 70 tosecure the head of the cap screw to a specially preformed flat area 71of the shroud ring. In the embodiment of FIG. 5, the inner face of thecap screw head fits flush against the flattened area 71 of the shroudring. The embodiment of FIG. 6 is similar to that of FIG. 5 except thatin place of the local welding, the flattened areas of the shroud ringare each provided with one or more tangs 73 stamped from the shroud ringand bent upward to resiliently engage a side of the cap screw head andthereby provide a spring tension for preventing loosening of the capscrews during operation.

Each of the above embodiments are illustrated with the shank 62b of thecap screws extending through a generally central portion of the path ofcirculating fluid; the presence of the cap screw shanks offer verylittle interference with the toroidal fluid flow therethrough and can bedisregarded for most design characteristics. The present inventionprovides a highly economical and easily adaptable means for insuringretention of the vanes in proper alignment throughout all operatingconditions while retaining the simplicity of sheet metal constructionheretofore found most desirable in making the shroud ring and vanes.

While the preferred embodiments of the present invention have been shownand described herein, it is obvious that many structural details may bechanged without departing from the spirit and scope of the appendedclaim.

I claim:

In a hydrodynamic coupling, an impeller assembly, comprising: a hollow,substantially semi-toroidal housing having a plurality of slots bothradially and circumferentially spaced; a semi-toroidal shroud in saidhousing and spaced from the interior wall thereof and having a pluralityof openings extending therethrough and spaced radially andcircumferentially thereof; a plurality of thin vanes having arcuateinner and outer edges meeting with the inner surfaces of said housingand the shroud respectively, said vane edges having tabs projectingoutwardly therefrom, said tabs on one edge fitting within said slots andextending outwardly therefrom to engage the housing side, and other ofsaid tabs extending through the openings in said shroud and engage theopposite side of said shroud, said housing having a greater thicknessthan said shroud and said housing having formed thereon a plurality ofthreaded socket portions facing the interior of the housing; a pluralityof cap screws contained wholly within the shell outer surface having oneend extending through openings in said shroud and engaging the oppositeside thereof, the other end of said cap screw being threadably receivedby a socket portion in said housing in a manner to draw the shroud andhousing together to apply compressive stresses to the edges of saidvanes for preventing disalignment of said vanes under all operatingconditions; and locking means associated with said shroud and cap screwsto prevent turning of the screws during operation of the coupling, saidlocking means comprising a resilient retainer plate for each of said capscrews and disposed chordally of said shroud, each retainer plate havingopposite edges in engagement with the shroud and imparting a resilientlocking force against said screws.

References Cited in the file of this patent UNITED STATES PATENTS2,371,588 Salerni Mar. 13, 1945 2,371,589 Salerni Mar. 13, 19452,692,562 Zeidler Oct. 26, 1954 2,998,782 Ryan et a1. Sept. 5, 1961

